[boost] Re: [date_time] fractional_seconds: documentation suggestions

From: Bart (bartmann.nsd_at_[hidden])
Date: 2005-06-08 13:09:12

On Wed, 08 Jun 2005 12:35:31 -0400, Caleb Epstein wrote:

> I think the specification of "fractional_seconds" in the time_duration
> class is unclear.  Using the multi-argument constructor, and passing
> 1000 for the 4th argument, am I specifying milliseconds? Microseconds?
> Does it depend on the compile-time resolution of the class?  If so
> (which is my suspicion), then using the 4-argument form of the ctor
> can lead to incorrect results if the resolution is changed.  That
> seems like a bad thing.
> 

Yes it does depend on the compile time resolution. In the following:
 time_duration td(1,2,3,1000);
The fractional_seconds parameter is 1000 units. That may be 1000
microseconds or 1000 nanoseconds.

In cases where the fractional_seconds exceeds the compiled resolution, the
extra value is carried over into the seconds field:
 time_duration td(1,2,3,123456789);
When compiled with microsecond resolution produces "01:04:06.456789".

I've updated the documentation to try and make this behavior more clear.
Thanks for bringing this to our attention.

Jeff will have to address the floating point issue.

Bart